Lotto#4644
A popular lottery operates under the following rules: from a set of balls, balls are randomly selected as the winning combination. Players win if they correctly predict this exact set of balls. Calculating the number of combinations for choosing balls from a set of balls is straightforward.
Write a program to determine the exact number of balls, , that need to be selected from a set of balls, given that the number of combinations is .
The input consists of a single line with two numbers: and , where 1 \leq N \leq 500\,000.
The output should be a single line containing the number , which is the number of balls that need to be selected.
Example 1